JP6594360B2 - Filter device - Google Patents

Description

  The present invention relates to a filter device including a plurality of capacitors.

  A filter circuit that is inserted into a power line or a signal line and used is known. Such a filter circuit is used for removing a high-frequency noise component generated on a power supply line or a signal line.

  As such a filter circuit, a π-type filter circuit configured by connecting capacitors to both ends of an inductor may be used. For example, Japanese Patent Laying-Open No. 2015-167352 (Patent Document 1) discloses such a π-type filter circuit. In the π-type filter circuit, a capacitor having a relatively large capacity such as a film capacitor is used.

  Since a capacitor having a relatively large capacity, such as a film capacitor, usually needs to be connected using a lead wire, the high-frequency noise removal performance is deteriorated due to the inductance of the lead wire. Therefore, in order to improve the high-frequency component removal performance, a capacitor having a small inductance, such as a feedthrough capacitor, may be used in parallel with the film capacitor. Patent Document 1 discloses a filter device in which a film capacitor and a feedthrough capacitor are connected in parallel.

JP, 2015-167352, A

  However, pulse noise with high intensity was applied to the filter device, and this pulse noise contained a component having the same frequency as the LC resonance frequency formed by the inductance of the lead wire of the film capacitor and the capacitance of the feedthrough capacitor. In this case, a large resonance current flows through the capacitor at this resonance frequency. In such a case, it is necessary to select a capacitor with a high withstand current so that the capacitor is not destroyed by the resonance current, and there is a problem that the capacitor becomes large.

  On the other hand, Patent Document 1 discloses means for reducing the electromagnetic coupling between the film capacitor on the input side and the film capacitor on the output side of the π-type filter circuit. However, the mechanism for reducing the resonance current itself is disclosed. It has not been. Therefore, there is a demand for a filter device that can reduce the size of the capacitor by reducing the resonance current that flows when pulse noise is applied.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a small filter device by reducing a resonance current flowing when pulse noise is applied.

  The filter device disclosed in the present disclosure is a filter device that removes noise of a signal line. The filter device includes a conductive casing, a first capacitor, a second capacitor, and an energy absorbing member. The first capacitor has a first electrode and a second electrode, the first electrode is connected to the conductive casing, and the second electrode is connected to the signal line. The second capacitor has a third electrode and a fourth electrode, the third electrode is connected to the housing, and the fourth electrode is connected to the second electrode. The second capacitor has a smaller capacitance than the first capacitor. The energy absorbing member is configured to absorb energy of magnetic flux passing through a space between the first wiring connecting the second electrode and the fourth electrode and the housing.

  According to the present invention, when pulse noise with high intensity is applied to the filter device, the resonance current flowing through the first capacitor and the second capacitor is reduced, and the first capacitor and the second capacitor can be reduced in size. .

1 is a circuit diagram of a filter device according to Embodiment 1. FIG. 2 is a top view of the filter device according to Embodiment 1. FIG. 1 is a side view of a filter device according to Embodiment 1. FIG. 1 is a perspective view of a filter device according to Embodiment 1. FIG. It is a figure for demonstrating arrangement | positioning of an energy absorption member. 6 is a side view of a filter device according to Modification 1 of Embodiment 1. FIG. 6 is a perspective view of a filter device according to a second modification of the first embodiment. FIG. 6 is a perspective view of a filter device according to a third modification of the first embodiment. FIG. 6 is a perspective view of a filter device according to a fourth modification of the first embodiment. FIG. It is the figure which compared and showed the capacitor | condenser current with and without a resonance energy absorption member. 6 is a perspective view of a filter device according to Embodiment 2. FIG. 6 is a perspective view of a filter device according to Embodiment 3. FIG. 6 is a circuit diagram of a filter device according to Embodiment 4. FIG. 6 is a perspective view of a filter device according to Embodiment 4. FIG. FIG. 10 is a circuit diagram of a filter device according to a fifth embodiment. 10 is a perspective view of a filter device according to Embodiment 5. FIG. FIG. 10 is a perspective view of a filter device according to a sixth embodiment. FIG. 10 is a perspective view of a filter device according to a modification of the sixth embodiment. FIG. 10 is a circuit diagram of a filter device according to a seventh embodiment. FIG. 10 is a circuit diagram of a filter device according to a modification of the seventh embodiment. FIG. 10 is a top view of a filter device according to an eighth embodiment. FIG. 10 is a perspective view of a filter device according to an eighth embodiment. FIG. 10 is a circuit diagram of a filter device according to a ninth embodiment. FIG. 10 is a top view of a filter device according to a ninth embodiment. 10 is a perspective view of a filter device according to Embodiment 9. FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

Embodiment 1 FIG.
First, the filter device according to Embodiment 1 of the present invention will be described. FIG. 1 is a circuit diagram of a filter device according to the first embodiment. FIG. 2 is a top view of the filter device according to the first embodiment. FIG. 3 is a side view of the filter device according to the first embodiment. FIG. 4 is a perspective view of the filter device according to the first embodiment.

  The filter device 100 includes an electrical filter (filter circuit) that is inserted into a signal line and used to remove noise in the signal line. The filter device 100 may be used by being inserted into a power line. The filter device 100 functions as, for example, a low-pass filter that removes high-frequency unnecessary components or a band-pass filter that removes frequency components other than a specific frequency.

  As shown in FIGS. 1 to 4, the filter device 100 includes an input terminal 101, an output terminal 102, a housing 5, film capacitors 11 a and 11 b, feedthrough capacitors 2 a and 2 b, wirings 12 a and 12 b, An inductor 3a and a resonance energy absorbing member 4a are provided.

  The filter device 100 is a filter device that removes noise in a signal line. The film capacitor 11a has a first electrode P1 and a second electrode P2. The first electrode P1 is connected to the conductive casing 5, and the second electrode P2 is connected to the signal line. The feedthrough capacitor 2a has a third electrode P3 and a fourth electrode P4. The third electrode P3 is connected to the housing 5, and the fourth electrode P4 is connected to the second electrode P2. The feedthrough capacitor 2a has a smaller capacitance than the film capacitor 11a. The energy absorbing member 4a is configured to absorb the energy of magnetic flux that passes through the space between the first wiring 12a that connects the second electrode P2 and the fourth electrode P4 and the housing 5.

  The housing 5 is a conductive case that houses the filter circuit and shields the filter circuit from the outside. The housing 5 is grounded (connected to the ground). The material of the housing 5 is, for example, aluminum or stainless steel. The housing 5 suppresses electromagnetic waves radiated from the filter circuit from being radiated to the outside of the housing, and suppresses electromagnetic waves from entering the filter circuit from the outside of the housing.

  The case 5 may have a box shape for sealing the filter circuit, or may have a bowl shape or a frame shape with an opening in a part thereof. In the present embodiment, it is assumed that the housing 5 has a box shape. However, for easy understanding, FIG. 2 shows a top view when the top surface of the housing 5 is removed (that is, when the housing 5 is bowl-shaped), and FIG. FIG. 4 shows a side view when the side surface is removed (that is, when the housing 5 has a bowl shape), and FIG. 4 shows a perspective view when the upper surface and the side surface of the housing 5 are removed.

  The inductor 3a is a coil formed by winding a copper wire or the like around a core member having a high magnetic permeability such as iron or ferrite.

  The feedthrough capacitors 2a and 2b are capacitors for passing the signal line through the housing 5 while insulating the housing 5 from the signal line. Each of the feedthrough capacitors 2 a and 2 b has a first electrode connected to the signal line and a second electrode connected to the housing 5. The first electrode is disposed so as to penetrate the wall surface of the housing 5, and includes two terminals on the outside and the inside of the housing 5. Hereinafter, the outer terminal of the housing 5 is referred to as an external terminal, and the inner terminal of the housing 5 is referred to as an internal terminal. The second electrode includes a ground terminal that is electrically connected to the housing 5.

  Each of the feedthrough capacitors 2a and 2b has a predetermined capacitance value (abbreviated as capacitance) between the signal line and the ground terminal. By installing the through capacitors 2 a and 2 b in the through holes provided in the housing 5, the through capacitors 2 a and 2 b penetrate the housing 5. An internal terminal enters the inside of the housing 5, and an external terminal exists outside the housing 5. The ground terminal is connected to the housing 5.

  The internal terminal of the feedthrough capacitor 2a is connected to one end of the inductor 3a, and is connected to one end of the film capacitor 11a by a wiring 12a. The other end of the film capacitor 11a is connected to the housing 5 by a wiring 13a. An external terminal of the feedthrough capacitor 2 a is connected to the input terminal 101 of the filter device 100.

  The internal terminal of the feedthrough capacitor 2b is connected to the other end of the inductor 3a and is connected to one end of the film capacitor 11b by a wiring 12b. The other end of the film capacitor 11b is connected to the housing 5 by a wiring 12b. An external terminal of the feedthrough capacitor 2 b is connected to the output terminal 102 of the filter device 100.

  Capacitors having a relatively large capacity, such as film capacitors 11a and 11b, need to be connected using normal wirings 12a and 12b. For this reason, high-frequency noise removal performance is degraded due to the inductance of the wirings 12a and 12b. On the other hand, the feedthrough capacitors 2a and 2b have a small parasitic inductance. Specifically, the parasitic inductances of the feedthrough capacitors 2a and 2b are smaller than the inductances of the wirings 12a and 12b.

  The feedthrough capacitors 2a and 2b are capacitors having low impedance at high frequencies, excellent high frequency attenuation characteristics, and excellent removal of high frequency components. The feedthrough capacitors 2a and 2b are made of a dielectric ceramic, a multilayer electrode, or the like. The capacitances of the feedthrough capacitors 2a and 2b may not be so large as compared with the capacitances of the film capacitors 11a and 11b. The capacities of the feedthrough capacitors 2a and 2b are set to appropriate capacities for removing high frequency components, and are smaller than the capacities of the film capacitors 11a and 11b. For example, the capacitance of the film capacitor is about 0.1 μF to 10 μF, whereas the capacitance of the feedthrough capacitor may be about 10 pF to 1000 pF. In addition, the high frequency here means a frequency of 1 MHz to 1 GHz.

  Thus, by using a capacitor having a small inductance, such as a feedthrough capacitor, connected in parallel to the film capacitor, the high frequency component removal performance of the filter device can be improved. In this embodiment, a plastic film is used as the dielectric of the film capacitors 11a and 11b. However, a ceramic capacitor whose dielectric is ceramic may be used.

  The filter device 100 according to the present embodiment includes a π-type filter (CL) including a parallel circuit of a feedthrough capacitor 2a and a film capacitor 11a, an inductor 3a, and a parallel circuit of a feedthrough capacitor 2b and a film capacitor 11b. -C type filter). With this π-type filter, the filter device can attenuate unnecessary noise components and output only a desired signal to the output terminal 102 when noise is applied to the input terminal 101.

  At this time, when a strong pulse noise including the same frequency component as the resonance frequency F of the LC resonance formed by the capacitance C of the feedthrough capacitor 2a and the inductance L of the wiring 12a of the film capacitor 11a is applied to the input terminal 101, A large resonance current flows through the feedthrough capacitor 2a and the film capacitor 11a. When the capacitance of the film capacitor 11a is sufficiently larger than the capacitance of the feedthrough capacitor 2a and the inductance of the wiring 12a is sufficiently larger than the parasitic inductance of the feedthrough capacitor 2a, the resonance frequency F can be obtained using the following approximate expression (1). .

  In this embodiment, as shown in FIGS. 3 and 4, a plate-shaped resonance energy absorbing member 4 a is provided in a space between the wiring 12 a connected to the film capacitor 11 a on the input terminal 101 side and the housing 5. The space between the wiring 12a and the housing 5 is a space through which magnetic flux lines generated when current flows through the film capacitor 11a. The resonance energy absorbing member 4a is disposed in this space. Then, when the resonance current flows through the film capacitor 11a, the magnetic flux generated from the wiring 12a connected to the film capacitor 11a is absorbed as resonance energy by the resonance energy absorbing member 4a. Therefore, the resonance current flowing through the film capacitor 11a and the feedthrough capacitor 2a can be reduced.

  FIG. 5 is a diagram for explaining the arrangement of the energy absorbing members. As shown in FIGS. 4 and 5, the housing has at least a first wall surface 15. The resonance energy absorbing member 4a has a conductor surface having a plane parallel to the plane 14 including the line segment 16 obtained by projecting the first wiring 12a onto the first wall surface 15 from the direction orthogonal to the first wall surface 15 and the first wiring 12a. Prepare.

  For example, as shown in FIG. 4, the resonance energy absorbing member 4a includes a surface perpendicular to the magnetic flux 6 generated between the housing 5 and the wiring 12a when a current flows through the wiring 12a, and the resonance energy absorbing member 4a. It is placed so that its wide surface is parallel. The resonance energy absorbing member 4a may not be electrically connected to the housing 5, but may be connected. When the resonance energy absorbing member 4a is electrically connected to the housing 5, the housing 5 also functions as a part of the resonance energy absorbing member. Further, the resonance energy absorbing member may be a block shape instead of a plate shape. In this case, the block-shaped wide surface is arranged so as to be parallel to a surface perpendicular to the magnetic flux.

  The resonance energy absorbing member 4a is made of a conductive material such as stainless steel, iron, carbon, copper, and aluminum. When a large resonance current flows through the film capacitor 11a, a magnetic flux 6 is generated between the wiring 12a and the housing 5. Therefore, an eddy current flows through the resonance energy absorbing member 4a so as to prevent the magnetic flux from being generated. Can be absorbed as eddy current loss.

  Therefore, the resonance current flowing through the feedthrough capacitor 2a and the film capacitor 11a can be reduced, and the feedthrough capacitor 2a and the film capacitor 11a can be downsized. Furthermore, since the resonance current decreases, the noise component output to the output terminal 102 can also be reduced.

  The resonance energy absorbing member 4a may be a magnetic material. In this case, a material that easily generates magnetic loss at the resonance frequency F (a material having a large imaginary component of magnetic permeability) is selected. An example of a material having such characteristics is ferrite. Thus, when a magnetic flux generated between the wiring 12a and the housing 5 enters the resonance energy absorbing member 4a when a large resonance current flows through the film capacitor 11a, the resonance energy is effectively absorbed as a magnetic loss. . For this reason, the resonance current flowing through the film capacitor 11a and the feedthrough capacitor 2a can be reduced.

  In the present embodiment, the feedthrough capacitor 2a is used as a capacitor having a small parasitic inductance, but a capacitor connected by a shorter wire than the wire 12a of the film capacitor 11a, such as a chip shape or a thin plate shape capacitor, instead of the feedthrough capacitor. Resonant current reduction effect can be obtained even if the capacitor is used, and in this case, the capacitor does not necessarily have to penetrate the casing.

  FIG. 6 is a side view of the filter device according to the first modification of the first embodiment. In the first modification, the resonance energy absorbing member 4 b is also provided in the space between the wiring 12 b connected to the film capacitor 11 b on the output terminal 102 side and the housing 5. In this case, the noise component output to the output terminal 102 can be further reduced.

  FIG. 7 is a perspective view of a filter device according to a second modification of the first embodiment. FIG. 8 is a perspective view of a filter device according to the third modification of the first embodiment. FIG. 9 is a perspective view of a filter device according to a fourth modification of the first embodiment.

  As shown in FIG. 7, the resonance energy absorbing member 4 a is not necessarily arranged in a space between the wiring 12 a and the housing 5 where the distance between the wiring 12 a and the surface of the housing 5 is the shortest. Alternatively, they may be arranged in parallel with the direction of the magnetic flux 6. Further, the resonance energy absorbing member 4a may be composed of a plurality of members so that a large amount of resonance energy can be absorbed as shown in FIGS.

  FIG. 10 is a diagram comparing the capacitor current with and without the resonant energy absorbing member. FIG. 10 shows a calculation example of the capacitor current flowing through the film capacitor 11a when the present embodiment is applied. The capacitor current I1 when the resonance energy absorbing member 4a is present can be significantly reduced as compared with the capacitor current I0 when there is no resonance energy absorbing member 4a.

  As described above, in the filter devices 100 and 100A to 100C according to the first embodiment and the modification, the capacitor parallel circuit in which the film capacitor 11a and the feedthrough capacitor 2a are connected in parallel is mounted on the conductive casing 5. Yes. The capacitance of the film capacitor 11a is larger than the capacitance of the feedthrough capacitor 2a, and the parasitic inductance of the wiring 12a connected to the film capacitor 11a is larger than the parasitic inductance of the feedthrough capacitor 2a. The filter device 100 includes a resonance energy absorbing member 4a in a space between the wiring 12a connected to the film capacitor 11a and the housing 5.

  By adopting such a configuration, when high-intensity pulse noise is applied to the filter devices 100, 100A to 100C, the resonance energy absorption member 4a reduces the resonance current flowing through the film capacitor 11a and the feedthrough capacitor 2a. The film capacitor 11a and the feedthrough capacitor 2a can be downsized. Furthermore, since the resonance current decreases, the noise component output to the output terminal can also be reduced.

Embodiment 2. FIG.
Next, a filter device according to Embodiment 2 will be described. FIG. 11 is a perspective view of the filter device according to the second embodiment. The filter device 200 according to the second embodiment basically has the same configuration as that of the filter device 100 according to the first embodiment, but the resonance energy absorbing member 41 surrounds the wiring 12a connected to the film capacitor 11a. It is different in that it is placed in.

  With this configuration, a larger amount of magnetic flux than in the first embodiment can be passed through the resonance energy absorbing member 41, and a large amount of resonance energy can be absorbed.

Embodiment 3 FIG.
Next, a filter device according to Embodiment 3 will be described. FIG. 12 is a perspective view of the filter device according to the third embodiment. The filter device 300 according to the third embodiment basically includes the same configuration as that of the filter device 100 according to the first embodiment, but the resonance energy absorbing member 42 is configured by a loop-shaped hollow conductive member. It is different in point. As shown in FIG. 12, the resonance energy absorbing member 42 has an annular shape through which the magnetic flux lines pass through the hollow portion.

  The resonance energy absorbing member 42 is disposed so that the magnetic flux 6 generated between the housing 5 and the wiring 12a when the current flows through the wiring 12a passes through the hollow portion of the resonance energy absorbing member 42. In the configuration shown in FIG. 12, when a large resonance current flows through the film capacitor 11 a, a magnetic flux 6 is generated between the wiring 12 a and the housing 5, so that the induced current I is applied to the resonance energy absorbing member 42 so as to prevent the magnetic flux 6. Flows. Thereby, resonance energy can be absorbed as induced current loss. The material of the resonance energy absorbing member 42 is a conductive material having a high resistivity such as stainless steel, iron, carbon, etc., but even when a good conductor such as aluminum or copper is used, the resistance element 43 is inserted in the middle of the loop, thereby increasing the resistance. The element 43 can absorb the resonance energy. The resonance energy absorbing member 42 does not have to be electrically connected to the housing 5 and may be connected. The filter device 300 according to the third embodiment can absorb resonance energy with a smaller amount of members than in the first embodiment.

Embodiment 4 FIG.
Next, a filter device according to Embodiment 4 will be described. FIG. 13 is a circuit diagram of a filter device according to the fourth embodiment. FIG. 14 is a perspective view of a filter device according to the fourth embodiment. The filter device according to the fourth embodiment basically has the same configuration as the filter device according to the first embodiment, except that the resistance element 7 is inserted in the middle of the wiring 12a connected to the film capacitor 11a. Different. That is, as shown in FIG. 14, the filter device 400 further includes a resistance element 7 provided in the middle of the first wiring 12 a in addition to the configuration of the filter device 100.

  When a large resonance current flows through the film capacitor 11a, the resonance energy absorbing member 4a not only absorbs the resonance energy, but also the resistance element 7 can absorb the resonance energy, and the resonance flowing through the feedthrough capacitor 2a and the film capacitor 11a. The current can be greatly reduced.

Embodiment 5 FIG.
Next, a filter device according to Embodiment 5 will be described. FIG. 15 is a circuit diagram of a filter device according to the fifth embodiment. FIG. 16 is a perspective view of a filter device according to the fifth embodiment. The filter device 500 according to the fifth embodiment basically has the same configuration as the filter device 100 according to the first embodiment, but a film capacitor is provided in the middle of the wiring 23 connecting the feedthrough capacitor 2a and the inductor 3a. 11a is connected by a wiring 12a shorter than the wiring 23, and differs in that a plate-like conductive resonance energy absorbing member 4a is provided in a space between the wiring 23 and the housing 5.

  In the present embodiment, the film capacitor 11a and the inductor 3a are mounted on the printed circuit board 81, the wiring 12a connected to the film capacitor 11a is formed by a wiring pattern on the printed circuit board 81, and one end of the film capacitor 11a is connected to the wiring 12a. And is connected to the housing 5 with a screw 82.

  When a large resonance current flows through the film capacitor 11 a, a magnetic flux 6 is generated between the wiring 23 and the housing 5. When an eddy current flows through the resonance energy absorbing member 4a so as to prevent this magnetic flux, the resonance energy can be absorbed as an eddy current loss. The resonance energy absorbing member 4a may be a magnetic material. In the present embodiment, unlike the first embodiment, since most of the magnetic flux 6 is generated from the wiring 23, a plate-shaped resonance energy absorbing member is not provided in the space between the wiring 23 and the housing 5 but in the wiring 12a. By providing 4a, the resonance current can be reduced.

Embodiment 6 FIG.
Next, a filter device according to Embodiment 6 will be described. FIG. 17 is a perspective view of a filter device according to the sixth embodiment. The filter device 600 according to the sixth embodiment basically includes the same configuration as the filter device 500 according to the fifth embodiment, but includes a resonance energy absorbing member 41 instead of the resonance energy absorbing member 4a. The resonance energy absorbing member 41 is different from the resonance energy absorbing member 4a in that it is arranged so as to surround the wiring 23. With the configuration of the present embodiment, more magnetic flux can be passed through the resonance energy absorbing member 41 than in the fifth embodiment, and a large amount of resonance energy can be absorbed.

  FIG. 18 is a perspective view of a filter device according to a modification of the sixth embodiment. The filter device 600A of this modification is different in that the resonance energy absorbing member 41 is arranged so as to surround not only the wiring 23 but also the film capacitor 11a. With the configuration of this modification, the film capacitor 11a can be shielded, electromagnetic coupling between the film capacitor 11a and the film capacitor 11b can be reduced, and the noise component output to the output terminal 102 can be further reduced.

Embodiment 7 FIG.
Next, a filter device according to Embodiment 7 will be described. FIG. 19 is a circuit diagram of a filter device according to the seventh embodiment. The filter device 700 according to the seventh embodiment basically has the same configuration as that of the filter device according to the first to sixth embodiments, but the inductor 3a and the feedthrough capacitor are provided between the feedthrough capacitor 2a and the feedthrough capacitor 2b. 2 is different from the first embodiment in that a C-L-C-L-C filter is configured as a whole by including a L-C-L circuit composed of a parallel circuit of 2c and a film capacitor 11c and an inductor 3b. In the filter device configured as described above, when a large resonance current flows through the film capacitor 11a, the resonance energy absorbing member 4a can absorb the resonance energy, and the resonance current flowing through the feedthrough capacitor 2a and the film capacitor 11a is reduced. it can.

  FIG. 20 is a circuit diagram of a filter device according to a modification of the seventh embodiment. Like the filter device 700A shown in FIG. 20, the feedthrough capacitor 2c may be removed from the central capacitor parallel circuit of FIG. With the configuration of this modification, the noise component output to the output terminal 102 can be further reduced.

Embodiment 8 FIG.
Next, a filter device according to Embodiment 8 will be described. FIG. 21 is a top view of the filter device according to the eighth embodiment. FIG. 22 is a perspective view of the filter device according to the eighth embodiment.

  The filter device 800 according to the eighth embodiment basically includes the same configuration as the filter device according to the first to sixth embodiments, but the housing 5 includes a parallel circuit of the feedthrough capacitor 2a and the film capacitor 11a. An inductor 3a, a first CLC circuit (first line) composed of a parallel circuit of a feedthrough capacitor 2b and a film capacitor 11b, a parallel circuit of a feedthrough capacitor 2d and a film capacitor 11d, an inductor 3d, And the second CLC circuit (second line) configured by a parallel circuit of the feedthrough capacitor 2e and the film capacitor 11e is different.

  More specifically, as shown in FIGS. 21 and 22, the filter device 100 includes a housing 5, film capacitors 11a to 11d, feedthrough capacitors 2a to 2d, wires 12a and 12d, and inductors 3a and 3d. And resonance energy absorbing members 4a and 4d.

  The filter device 300 is a filter device that removes noise from the first signal line S1 and the second signal line S2. The film capacitor 11a has a first electrode P1a and a second electrode P2a, the first electrode P1a is connected to the conductive casing 5, and the second electrode P2a is connected to the first signal line S1. The feedthrough capacitor 2a includes a third electrode P3a and a fourth electrode P4a. The third electrode P3a is connected to the housing 5, and the fourth electrode P4a is connected to the second electrode P2a. The feedthrough capacitor 2a has a smaller capacitance than the film capacitor 11a. The energy absorbing member 4a is configured to absorb the energy of magnetic flux passing through the space between the housing 5 and the first wiring 12a that connects the second electrode P2a and the fourth electrode P4a.

  The film capacitor 11d has a fifth electrode P1d and a sixth electrode P2d, the fifth electrode P1d is connected to the conductive casing 5, and the sixth electrode P2d is connected to the second signal line S2. The feedthrough capacitor 2d has a seventh electrode P3d and an eighth electrode P4d. The seventh electrode P3d is connected to the housing 5, and the eighth electrode P4d is connected to the sixth electrode P2d. The feedthrough capacitor 2d has a smaller capacitance than the film capacitor 11d. The energy absorbing member 4d is configured to absorb the energy of magnetic flux passing through the space between the housing 5 and the second wiring 12d that connects the sixth electrode P2d and the eighth electrode P4d. In the filter device configured as described above, when a large resonance current flows through the film capacitor 11a and the film capacitor 11d, the resonance energy absorbing member 4a and the resonance energy absorbing member 4d can absorb the resonance energy, and the feedthrough capacitor 2a The resonance current flowing through the film capacitor 11a and the resonance current flowing through the feedthrough capacitor 2d and the film capacitor 11d can be reduced.

  As shown in FIG. 21, by mounting the resonance energy absorbing member on both the first line and the second line, the resonance current flowing through the capacitors on both lines can be reduced. In the present embodiment, a filter device equipped with two lines is shown, but the filter device may have three or more lines.

Embodiment 9 FIG.
Next, a filter device according to Embodiment 9 will be described. FIG. 23 is a circuit diagram of a filter device according to the ninth embodiment. FIG. 24 is a top view of the filter device according to the ninth embodiment. FIG. 25 is a perspective view of the filter device according to the ninth embodiment. The filter device 900 according to the ninth embodiment basically has the same configuration as the filter device 800 according to the eighth embodiment, but one end of the film capacitor 21a is connected to the feedthrough capacitor 2a via the wiring 22a. The other end of the film capacitor 21a is different in that it is connected to the feedthrough capacitor 2d via the wiring 22a.

  Specifically, the filter device 900 removes noise from the first signal line S1 and the second signal line S2. The filter device 900 includes a conductive housing 5, feedthrough capacitors 2 a and 2 d, a film capacitor 21 a, and an energy absorbing member 44.

  The feedthrough capacitor 2a has a first electrode P11a and a second electrode P12a, the first electrode P11a is connected to the conductive casing 5, and the second electrode P12a is connected to the first signal line S1.

  The feedthrough capacitor 2d has a third electrode P11d and a fourth electrode P12d, the third electrode P11d is connected to the conductive casing 5, and the fourth electrode P12d is connected to the second signal line S2.

  The film capacitor 21a has a fifth electrode P15 and a sixth electrode P16, the fifth electrode P15 is connected to the second electrode P12a, and the sixth electrode P16 is connected to the fourth electrode P12d. The film capacitor 21a has a larger capacitance than the feedthrough capacitors 2a and 2d.

  The energy absorbing member 44 includes at least a part of the first wiring 22a that connects the second electrode P12a and the fifth electrode P15 and at least a part of the second wiring 22d that connects the fourth electrode P12d and the sixth electrode P16. The energy of the magnetic flux 46 passing through the space between the housing 5 and the housing 5 is absorbed. In the filter device configured as described above, when a large resonance current flows through the film capacitor 21a, the resonance energy absorbing member 44 can absorb the resonance energy, and flows through the feedthrough capacitor 2a, the feedthrough capacitor 2d, and the film capacitor 21a. Resonance current can be reduced.

  In the configuration shown in the ninth embodiment, the resonance energy disposed in the space between the wiring 22a and the housing 5 is also applied when pulse noise having high differential intensity is applied between the input terminals 101 and 103. The absorbing member 4a can absorb resonance energy.

  Embodiments 1 to 9 described above may be used in combination with each other. The embodiment disclosed this time should be considered as illustrative in all points and not restrictive.

  2a, 2b, 2c, 2d, 2e feedthrough capacitor, 3a, 3b, 3d inductor, 4a, 4b, 41, 42 resonance energy absorbing member, 5 housing, 6 magnetic flux, 7, 43 resistance element, 11a, 11b, 11c, 11d, 11e, 21a Film capacitor, 12a, 12b, 22a, 23 Wiring, 14 plane, 15 plane, 16 line segment, 81 Printed circuit board, 82 Screw, 100, 200, 300, 400, 500, 600, 600A, 700, 700A, 800, 900 Filter device, 101 input terminal, 102 output terminal.

Claims (10)

A filter device for removing signal line noise,
A conductive housing;
A first capacitor having a first electrode and a second electrode, wherein the first electrode is connected to the conductive casing, and the second electrode is connected to the signal line;
A second capacitor having a third electrode and a fourth electrode, wherein the third electrode is connected to the housing, the fourth electrode is connected to the second electrode, and having a smaller capacitance than the first capacitor; When,
A filter device comprising: a first wiring that connects the second electrode and the fourth electrode; and an energy absorbing member that absorbs energy of magnetic flux passing through a space between the housing.   2. The filter device according to claim 1, wherein a space between the first wiring and the housing is a space through which a magnetic flux line generated when a current flows through the first capacitor passes.   The filter device according to claim 2, wherein the energy absorbing member is made of a conductive material.   The filter device according to claim 3, wherein the energy absorbing member has an annular shape through which the magnetic flux lines pass through a hollow portion.   The filter device according to claim 3, wherein the energy absorbing member is electrically connected to the housing.   The filter device according to claim 2, wherein the energy absorbing member is made of a magnetic material.   The filter device according to claim 2, further comprising a resistance element provided in the middle of the first wiring. The housing has at least a first surface;
The energy absorbing member includes a conductor surface having a plane parallel to a plane including a line segment obtained by projecting the first wiring onto the first surface from a direction orthogonal to the first surface and the first wiring. Item 2. The filter device according to Item 1. A filter device for removing noise of a first signal line and a second signal line,
A conductive housing;
A first capacitor having a first electrode and a second electrode, wherein the first electrode is connected to the conductive casing, and the second electrode is connected to the first signal line;
A second capacitor having a third electrode and a fourth electrode, wherein the third electrode is connected to the housing, the fourth electrode is connected to the second electrode, and having a smaller capacitance than the first capacitor; When,
A first energy absorbing member that absorbs energy of magnetic flux passing through a space between the housing and a first wiring connecting the second electrode and the fourth electrode;
A third capacitor having a fifth electrode and a sixth electrode, wherein the fifth electrode is connected to the conductive housing, and the sixth electrode is connected to the second signal line;
A fourth capacitor having a seventh electrode and an eighth electrode, wherein the seventh electrode is connected to the housing, the eighth electrode is connected to the sixth electrode, and having a smaller capacitance than the third capacitor; When,
A filter device comprising: a second wiring that connects the sixth electrode and the eighth electrode; and a second energy absorbing member that absorbs energy of magnetic flux passing through a space between the housing. A filter device for removing noise of a first signal line and a second signal line,
A conductive housing;
A first capacitor having a first electrode and a second electrode, wherein the first electrode is connected to the conductive casing, and the second electrode is connected to the first signal line;
A second capacitor having a third electrode and a fourth electrode, wherein the third electrode is connected to the conductive casing, and the fourth electrode is connected to the second signal line;
A fifth electrode and a sixth electrode; the fifth electrode is connected to the second electrode; the sixth electrode is connected to the fourth electrode; and more electrostatic than the first capacitor and the second capacitor A third capacitor having a large capacity;
Between the housing and at least a part of the first wiring connecting the second electrode and the fifth electrode and at least a part of the second wiring connecting the fourth electrode and the sixth electrode An energy absorbing member that absorbs energy of magnetic flux passing through the space.

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